An important use of vinyl chloride polymers is as a binder for nonwovens such as a paper saturant in making filter paper for air and oil filters. Such filters bonded with vinyl chloride polymer saturants and pleated should resist delamination and splitting. A further requirement is wet strength.
One of the problems with the use of chlorine-containing emulsion polymers such as vinyl chloride polymers in the saturation of fibrous substrates is the need to enhance the physical properties, particularly the wet strength of the polymers.
In the past, addition of melamine-formaldehyde resin to the emulsion has been used to improve the wet strength of the polymer. The resulting composition provided adequate wet strength but yielded a brittle product with poor flexural strength. The delamination resistance of the saturated fibrous substrate was also poor. Additionally, there was opposition in the industry due to the formaldehyde content of the resins because of possible toxicity and the high temperature required to obtain optimum properties.
It is also known to improve the properties of vinyl chloride polymers by crosslinking them with linear aliphatic polyamines such as polyethylenimine.
U.S. Pat. No. 3,410,811 discloses a granular, polyvinyl chloride-based anion exchange resin prepared by reacting a polyvinyl chloride resin with an aqueous solution of ammonia or aliphatic mono- and polyamines having less than 13 carbon atoms per molecule, at a temperature of at least 100.degree. C. and subsequently further reacting the aminated polyvinyl chloride resin with a polyfunctional compound having at least two amine-reactive groups.
U.S. Pat. Nos. 3,833,531 and 3,968,317 are representative of the art which shows reaction between a diallylamine polymer and an epihalohydrin such as epichlorohydrin.
U.S. Pat. No. 4,167,610 discloses reacting an allylamine type polymer with an organic dihalo compound to obtain an ion exchange resin.